A plurality of lambda probes on an internal combustion engine are used in two fundamentally different arrangements. In one arrangement, the plurality of probes is located in the exhaust-gas channel of the internal combustion engine at successive locations. In the other arrangement, the lambda probes are each mounted in an identical position in different component channels of the exhaust-gas channel system. The invention relates to an arrangement of the last-mentioned type.
An arrangement of this type is provided, for example, for the methods and devices according to U.S. Pat. No. 4,231,334 and published German application DE-Al-2,255,879 corresponding to U.S. Pat. application Ser. No. 401,195 and filed on 9-27-73. In each case, a lambda probe is arranged in the exhaust-gas component channel of each half of a V-type engine in front of the particular point before the two component channels are combined to form a manifold, in which a catalyst is arranged. In the method according to DE-Al-2,255,874, the signals of the two probes serve for supplying actual values for two separate control circuits, each of which is assigned to one half of the engine. In the method according to DE-Al-2,7l3,988, the signals of the two probes serve as actual values for a single control circuit. In accordance with the nature of the signals from the two probes, a decision is made as to whether the controller increases or decreases the regulating value or leaves it unchanged. Furthermore, the regulating value is wobbled as a function of a summed control deviation in such a way that, on top of the conventional oscillation of the two-position controller, the mixture alternates between rich and lean rapidly and continuously.
The known methods and devices serve for supplying air/fuel mixtures which result in exhaust gas of such a kind that harmful substances still present in the exhaust gas can be converted as efficiently as possible by means of a catalyst.
The object on which the invention is based is to provide a method for lambda control in an internal combustion engine with at least two lambda probes in an identical position, which allows an even better conversion of harmful substances than previous methods. A further object of the invention is to providing a device for carrying out such a process.